An example of a switching system to which the present invention applies is described in U.S. Pat. No. 5,544,163, Expandable Telecommunications System, the contents of which are incorporated herein by reference. The system comprises a plurality of programmable switching nodes and a host that exercises supervisory control over the switching nodes. The host is a group of software applications that typically reside on a computer to provide various supervisory and call control functions. The switching nodes are interconnected by an internodal switching network. A second network termed the "host network," interconnects the switching nodes and the host computer for supervisory control. Examples of the host supervisory applications include call control applications that control call switching functions in the switching nodes, call setup and teardown applications that perform call setup and teardown functions, billing applications that allocate costs to consumers who use the system, applications that incorporate ancillary services such as call forwarding and call waiting, and testing applications that test the performance of the switching nodes.
For the host to control the switching nodes, each host supervisory application must perform certain common administrative functions. These functions include access to switch configurations, switch monitoring, and switch diagnosis. The software for performing these common functions is duplicated in each of the supervisory applications. Accordingly, in order to maintain and upgrade these common administrative functions, all host supervisory applications must be correctly modified. Software errors may well result when changing the common functions by, among other things, failing to make the necessary changes in all the supervisory applications.
Moreover, as the number of supervisory applications increases so too does the time it takes to modify them. Thus, the system operator may then have to bring the system down in order to correctly change the administrative functions without causing errors in switching operations.